Crude oil demulsifiers

ABSTRACT

POLYOXYALKYLATED DERIVATIVES OF CARBAMIC ACIDS FOR USE AS QUICK-ACTING COLD DEMULSIFIERS FOR WATER-IN-OIL EMULSIONS.

- US. Cl. 260471 C nited States Patent 3,786,081 CRUDE OIL DEMULSIFIERS Knut Oppenlaender, Ludwigshafen, Gert Liebold, Mannheim, and Egon Buettner, Ludwigshafen, Germany, assignors to Badische Anilin- & Soda-Fabrik Aktiengesellschaft, Ludwigshafen am Rhine, Germany No Drawing. Filed Dec. 3, 1971, Ser. No. 204,723 Claims priority, application Germany, Dec. 4, 1970, P 20 59 707.3 Int. Cl. C07c 125/06 2 Claims ABSTRACT OF THE DISCLOSURE Polyoxyalkylated derivatives of carbamic acids for use as quick-acting cold demulsifiers for water-in-oil emulsions.

Polyoxyalkylated compounds such as block copolymers of ethylene oxide and/ or 1,2-propylene oxide are known, for example from US. Pat. 2,964,478. They are recommended for use as demulsifiers for oil-in-water emulsions containing predominantly water, but they are not suitable for use as demulsifiers for emulsions of inverse constituent proportions, that is, of water-in-oil emulsions containing predominantly oil. The segregation of the latter types of emulsion is, however, a particularly important problem in the mineral oil industry and a number of solutions thereto are known, but these solutions do not meet all requirements.

The previously known demulsifiers for water-in-oil emulsions, as disclosed for example in German published application DAS 1,545,250 and largely consisting of a variety of alkylene oxide polymers and compounds derived therefrom, all having hydrophilic end groups, are frequently too slow in action and usually act only at elevated temperatures. They leave unduly large concentrations of residual water or residual salt or residual emulsion or they give satisfactory results only with very special types of oil.

Usually, the tapped water-in-oil emulsions must be heated to temperatures above 40 C. and sometimes to as high as 80 C. depending on their viscosity, in order to achieve the desired low concentrations of water, salt and, in some cases, residual emulsion by a chemical process or combined chemical and electrical process. Such heating involves comparatively high energy consumption and it is thus desirable to find a way of breaking water-in-oil emulsions at the temperatures at which they are tapped, for example at from about to 40 C., by adding suitable demulsifiers Without applying heat.

It is an object of the invention to provide universally applicable demulsifiers for use industrially and which make it possible to break emulsions at ambient temperatures without heating or at least in a sufiiciently short time.

This object is achieved by crude oil demulsifiers which contain compounds of Formula I:

L Xn nmO\D m n mO/xHI (I) in which D denotes a bivalent radical derived from an aliphatic or aromatic, cycloaliphatic or aromatic-cycloaliphatic diisocyanate, A denotes the radical of the formula -OC H B denotes the radical of the formula OC H n and m are the same or different and denote integers between 10 and 200 and x is an integer from 0 to 5.

The structural unit A B A in the above formula is a block copolymer prepared in known manner from 1,2- propylene oxide and ethylene oxide. m and n may be the same or difierent and denote integers between 10 and 200.

3,786,081 Patented Jan. 15, 1974 Preferably, m and n denote integers between 15 and 100.

The block A and B may have the same molecular weight but usually have different molecular weights, the molecular weight of block A conveniently having a value which is at least 0.6 times the value of the molecular weight of block B.

This block copolymer A B A is reacted with diisocyanates. Suitable diisocyanates are aliphatic diisocyanates, aromatic-cycloaliphatic diisocyanates, aromatic diisocyanates, cycloaliphatic diisocyanates and, in particular, those diisocyanates whose aromatic and/or cycloali phatic rings are bridged by methylene groups.

Examples of diisocyanates which are particularly suitable for reaction with the blocks A B,,A are the fol lowing: toluylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, phenyleyclohexylmethane diisocyanate and nonadecadiisocyanate of the formula:

The preparation of the reaction products of the block copolymer polyalkylene glycol ethers with the diisocyanates may for example be carried out as follows: from 1 to 2 moles of the polyalkylene glycol ether are mixed with from 0.1 to 2 moles of one of the diisocyanates defined above. There are produced dior poly-urethane depending on the molar ratio. For example, if 2 moles of a polyalkylene glycol ether of the structure A B A are mixed with 1 mole of a diisocyanate and the two components are reacted with each other, the resulting diurethanes mainly have x=0. However, as the molar ratio approaches a ratio of 1:1 the corresponding polyurethanes are formed. In general, the polyurethanes formed have x equal to or less than 5.

The reaction is catalyzed by bases. Suitable bases are those which do not react with the isocyanates to form byproducts and which do not chemically attack the polyalkylene glycol ethers. We have found sterically hindered tertiary amines to be most suitable for this purpose.

Accordingly, examples of such amines which are useful for the process of the invention are tri-n-butylamine, tricyclohexylamine and triamylamine, the preferred amine being tri-n-butylamine due to its ready availability.

Other tertiary amines, such as trimethylamine or triethylamine, are less suitable for the present reaction.

The course of the reaction is simple and the reaction is carried out, for example, by reacting from 0.1 to 2 parts of diisocyanate with from 1 to 2 parts of a polyalkylene glycol ether (the parts being molar parts), which glycol ether has the structure A B A and contains from approximately 0.01 to 0.5% by Weight of tri-n-butylamine, the reaction being continued until the isocyanate titer is approximately 0. The reaction is preferably carried out under nitrogen or some other gas which is inert to the reaction and at temperatures between 25 and 70 C. and preferably between 30 and 40 C. In order to keep the product in solution more easily, the reaction may be carried out in the presence of organic solvents boiling between 70 and 200 C. Preferred solvents are aromatic compounds such as benzene, toluene, xylenes, carbon tetrachloride, dioxane and also petroleum ethers which boil within the stated range and other organic solvents which are inert to the reaction.

The use of said solvents becomes essential when the molar ratio of the reactants is such that the said polyurethanes are formed. In general these polyurethanes are highly viscous and less soluble in water so that agitation thereof in the reaction vessel without said solvents would be very difficult or impossible.

For commercial uses, the solvent may remain in the product. However, this is not necessary in all cases.

The individual products are characterized by certain values such as saponification values, acid values and hydroxyl values etc. The products are usually viscous to pasty substances which are colorless to pale yellow according to molecular weight and the nature of the diisocyanate having pour points which are at least 10 C. below the temperature at which they are tapped. Examples are the oils tapped in Knesebeck, Riihlermoor, Hankensbiittel, Berkhtipen, Steimke, Stelle (Lower Saxony), Landau (Upper Rhine Valley), Arlesried (Alpine Foreland) Parentis,

used. Mlmizan (Southwest France) and Bahrern (Middle East), The products may be used as such for breaking waterand numerous oils tapped in Caucasus and other parts of in-oil emulsions at ambient temperature, or, as already U.S.S.R. mentioned, they may be used in solution for this purpose. Other suitable o1ls are those from South America and They are distinguished by an extremely rapid demulsify- Mexico provided their pour point 1s more than 10 C. ing action. It is preferred to use them in the form of solubelow the treating temperature. tions. Suitable solvents are, for example, the aforemen- The separation of the Water-1n-o1l emulsions takes place tioned solvents, particularly cycloaliphatic or aromatic hywlthout heating extremely rap1dly and nearly quantitadrocarbons boiling in the approximately range 70 to lv ly- It e t have Q he p fy demulslfylng 200 C., such as cyclohexanol, ethylcyclohexanol, toluene 15 complete w1th1n a few minutes or, in stubborn cases, 1n and xylene. The solutions are conveniently adjusted to a t m e than from 1 to 2 hours. solids content of from 0.5 to 50% by weight. For the pur- Reaetlon Products Obtalhed from feaetloh mlxtllfes pose of rapid demulsitying of water-in-oil emulsions in the wh1ch contaln, as further reactant, polyoxyethylated 1S0- cold the products of the invention are added either as such alkylformaldehyde resms such as are described 1n French or in solution to the crude oil emulsions, preferably at Pat 1,566,470 Show I10 teehnleal advance r h ls the oil well. The demulsifying reaction takes place at the thahes and the p y h alone- T examples are temperature of the freshly ta ped water-in-oil mul ion lowed by a comparative table wh1ch l1st s the advantages at such a rate that the emulsion may break up o it way of the crude oil demulsifiers of the invent1on in clear comto the processing plant; Her it i readil separated i t parison against those demulsifiers ment1oned in said refercrude oil (dry oil) and salt Water in an appropriate unefleesheated separator in which an electric field may be used if EXAMPLE 1 cold demulsification is sluggish. In such difficult cases, a General re arafon small portion of the salt water remains in the crude oil in p p 1 in the separators. This necessitates further treatment in 2 moles of a polyalkylene glycol other having a molecuchemical or comblned chemical and electric plant treatl i ht f f o 2,000 to 8,000 are mixed with 0.25% ers) at elevated temperatures but there is now the s1gn1fib i h (b d on 1 1k 1 l l ether) of i cant advantage that the meler POYtlOIl 0f the Water has butylamine under an atmosphere of nitrogen, and to the already been remOVed and thus 10I1ger ne ed$ to he resulting mixture there are added dropwise from 0.1 to 2 heated. Moreover, due to the rap1d demulsifylng action ol of diisocyanate at from 30 to 40 C. The re- Of the p the 011 treated in this y is fully paction is complete after stirring the mixture for 3 hours arated within about 60-120 minutes. The fact that the at the same temperature under a blanket of nitrogen. The water no longer needs to be heated 1n 1ts 1111t1a1 amount in end of the reaction is indicated by the isocyanate titer fallmany cases 1s an mvaluable advantage since the speclfic ing to zero. If the reaction is carried out at molar ratios heat of Water E5 0(3T1) 15 about twlee as great leading to the formation of polyurethanes (ratio of polyas that of crude 011 (0.5 cal. gr C.- alkylene glycol ether to diisocyanate form about 1.5 :1 to The products to be used 1n accordance with the present 1:1), it is necessary to add organic solvents such as lnvention are valuable for separating salt water from toluene, crude oil from a wide variety of sources. These are added The advantages of the crude oil demulsifiers are clearly to the emuls1ons advantageously 1n proportions arrangshown in the following tables. Comparison is made with mg from 10- to 10- and preferably from 5x 10- to reaction mixtures which contain, as further reactant, iso- 5 1O percent by weight based on the weight of the alkylphenol/formaldehyde resins (in a molar ratio of emulsron to be separated, at temperatures ranging from 2:1:1, the latter figure indicating the proportion of resins), 10 to 40 C. referred to as MP in the tables. Products containing The demulsifiers may be used for separating water-inphenolic resins not containing any diisocyanate, referred oil emulsions containmg from about 0.1 to 90% by weight to as resin HP, are also listed for comparison. Further of salt water. Suitable oils which may be rapidly dehycomparison is also made with pure A B A block codrated at ambient temperature in this manner are those polymers, simply indicated by adash TABLE I Cold demulsifieation of Hankensbuttcl crude oil (50% H20) at 23 C. with 150 ppm. of demulsifier Isoalkyl- Total phenol] M.W.ofpoly- M.W.ofpoly- M.W.ot rm de- Molar Waterseparation (ml.)atter- Residual propylene ethylene poly- 0H Dilsocyanate hyde polyratio 01' water glycol ether glycol ether ether value component oxyethylate I:II or 10 30 content, Ex. portion n portion m portlonI otI II III I:II:III 2: min. min. min. min. percent 2, 300 40 1,200 14 3,500 43 Toluylene 2:1 0 4 15 25 48 1.0 MP 2,300 40 1,200 14 3,500 43 d0 (1) 21 1 3 10 17 35 15 HP- 3.5 (1) 2 0 20 20} Ca 15 2,300 40 1,200 14 3,500 43 0 Sp. Sp. 0

TABLE II Gold demulsification of Knesebeck crude oil (36% B10) at 26 C. using p.p.m. of demulslfier Isoalkyl- Tot phenol/ M.W.otpoly- M.W.otpoly- MW. of Diisocyaformalde- Molar Water separation (m1.) after- Residual propylene ethylene poly- 0H nate hyde polyratio of water glycol ether glycol ether ether value component oxyethylate 1:11 or 10 20 30 60 120 content, portion 71 portion m portionI olI II III I:II:III a: min. min. min. 11. min. percent 2,300 40 1,200 14 5 20 2s 30 32 3.5 2,300 40 1,200 14 4 18 25 27 28 8.0 H28 33 tilt it 8 5 5 i i 0 0 1 3 7 30 2,300 40 1,200 14 0 0 1 2 5 2,300 40 1, 200 14 5 1s 25 30 32 3.8 ,300 40 1, 200 14 5 20 23 30 31 4.0 2.4 2,300 40 1,200 14 3,500 3 1s 25 30 31 4.0 25..--.- 2,300 40 1,200 14 3, 500 43 Dlphenyl- 3 17 25 2s 31 5.2

methane.

TABLE III Rapid demulsification of Ruhlermoor crude oil (30% 1120) at 60 C. using 100 p.p.m. of demulsifier Isoalkyl- Total phenol/ Water separation Residual MW. of poly- MW. of poly- MW. of Diisocyaformalde- Molar (1111.) afterwater/ propylene ethylene poly- H note hyde poly ratio of residual glycol ether glycol ether ether value component oxyethylate 1:11 or 30 60 120 360 emulsion, portion 1; portion 'In portionI of I II III I:II:III a: min. min. min. min. percent 2,300 40 1,200 14 3,500 43 Toluylene 1.521 1-2 22 25 27 28 4/5.6 2,300 40 1,200 14 1.3:1 23 26 27 4/2.0 2,300 40 1,200 14 0 5 17 22 4.4/2.8 (1) 0 3 12 20 4.0/8.5

TABLE IV Rapid demulsification of Ruhlermoor crude oil 1110) at 60 C. using 30 p.p.m. of demulslder Isoalkylphenol/ Water MW. of poly- MW. of poly- Total formelde- Molar separation propylene ethylene M.W. of OH hyde polyratio of after 360 glycol ester glycol ether polyether value Diisocyenate oxyethylete 1:11 or min. in Ex. portion 1; portion m portionI of I component II III I:II:III ml.

2,500 36 2,050 24 4,100 Toluylene 2:1 0 22 2,250 39 2,250 26 500 34.2 2:1 0 23 2,750 48 1,850 21 4,600 28.5 2:1 0 26 3,250 2,150 25 5,800 26.5 2:1 0 19 3,250 50 3,250 30 6,500 19.3 2:1 0 23 2,300 40 1,200 14 3,500 43 1.7:1 1-2 20 2,300 40 1,200 14 3,500 43 1.2:1 3-4 18 2,300 40 1,200 14 3,500 43 1.1:1 4-5 19 2,300 40 1,200 14 3,500 43 1:1 5 19 MP 2,300 40 1,200 14 3,500 43 2:1:1 3 MP 1,750 30 1,200 14 2,950 51 2:1:1 1 2,300 40 1,200 14 3,500 43 1.5:1 1-2 23 2,300 40 1,200 14 3,500 43 1.3:1 2-3 29 1,750 1,200 14 2,950 51 2:1 0 24 1,500 25 1,000 12 2,600 2:1 0 23 2,300 40 1 00 14 3,500 43 14 MP 1,750 30 7,000 80 8,750 16.8 T0luy1ene (1) 21111 3 We claim: are the same or diiferent and denote integers between 10 1. Compounds of the formula: and 200 and x is an integer from 0 to 5.

2. Compounds as claimed in claim 1, wherein, in the f 35 formula, the molecular weight of the block A has a value m n m'- m n m H] which is at least 0.6 times the value of the molecular weight of block B.

References Cited in which D denotes a bivalent radical derived from toluyl- UNITED STATES PATENTS ene diisoe anate di hen methane diisoc anate hexa- 4 y p i 1 h h 2,695,913 11/1954 Bloch et :al. 260-471 0 methylene dusocyanate, p eny cyclo exy met ane duso- 3 365 412 H1968 Th 1 cyanate or nonadecadiisocyanate of the formula: mm at a 2 C C LORRAINE A. WEINBERGER, Primary Examin' er H =c=o 45 L. A. THAXTON, Assistant Examiner A denotes the radical of the formula -0C H B denotes the radical of the formula --OC H nand m 252-358; 260-775 AP, 468 E, 482 B 

